A creative family that has lasting memory, hides things, gives gifts, and otherwise either amuses, enchants or frustrates humans, the corvids are often the subject of research into intelligence in avian species. This is the first in a series looking at what the scientific community has found, with some insights from my own and others’ experiences.
Who are the corvids
Crows, ravens, rooks, magpies, jackdaws, jays, treepies, choughs, and nutcrackers are all members of the corvid family. Readers in the US will likely be familiar with most of these but may not know the Eurasian jay, jackdaws and choughs of Europe, or the treepies of Asia. It doesn’t matter; they all share some characteristics, particularly their high intelligence and creative thinking.
As animal consciousness research has evolved, scientists have settled on a set of five dimensions (Sensory Experience, Evaluative Experience, Experience of Self, Immediate Unity of Experience and Experience of Self Over Time) to help them, and us, understand what animals experience as consciousness. Let’s go through these dimensions one by one to get a clearer picture of how scientists are evaluating consciousness in these species.
Sensory experience
As any bird makes their way through complex environments, they need to be able to process what’s going on around them, what they need to do to eat, and how to avoid being some other species’ dinner. For this, they need to adjust to constantly changing conditions.
A. Vision is likely most important
One way of studying how birds see their environment is to look at flicker fusion-- when flickering light becomes a solid picture. Eurasian jays (Garrulus glandarius) were able to match objects in a video (flickering light) to real-life objects twice as fast as humans were. I don’t know about you, but I was impressed with that.
But how does that help them? By being able to resolve their view of what’s in front of them even faster than we do, they can more quickly find food, especially moving prey; avoid being predated by other animal, including humans; and better keep watch over their young.
Corvids also have the widest field of view of all passerines (sometimes called songbirds, although I don’t find this a satisfying label for the variety of birds in this group). And, of the corvids, the New Caledonian Crow (Corvus moneduloides), a resident of the South Pacific island chain it is named after, has the broadest. These crows are also famous for their tool use, they create stick tools of the right size and shape to extract grubs form tree cavities. To extract their meal, they hold the stick in their bill tip and press it against their cheek. Here’s where their field of vision comes into play: their wide field of view allows them to see both the tool and the space they are working in. This way they can more easily manage their task.
The Eurasian Jay, a more colorful corvid Photo by Petr Beneš on Unsplash
B. Hearing is also important in corvid lives
Another tool in the corvids’ toolbox is their sensitive hearing and ability to create elaborate vocal systems, sometimes called songs. But anyone who has listened to crows or ravens is not likely to call their communication song, except those who will accept atonal, grating sounds as a form of music.
Those clever Eurasian jays noted above use remembered acoustic information, such as the sounds made when food was being cached (hidden) by other birds, allowing them to steal from those caches. Carrion crows (Corvus corone) can tell the difference between the reliability of others of their species based on their alarm calls, kind of like identifying the boy who cried wolf.
C. Can you smell that?
Birds were long thought to be deficient in the ability to smell, but that has been proven not to be the case. Most birds have good olfactory capability and can identify other birds by their distinct plumage (feather) smell. While this sense is not as well-developed in the corvids as it is in some other avian species, corvids do use their sense of smell when foraging and finding or re-finding their caches and those of others.
In a test of black-billed magpies (Pica hudsonia), using food that was either heavily scented with cod liver oil or unscented, the magpies found the scented food faster. Ravens in another study were able to find fish using only scent clues. Despite these findings, sense of smell may not be as well developed in crows as it is in other avian species.
That covers our present knowledge of corvid sensory systems. Next time we’ll look at more about how corvids experience their sense of self, and maybe more.
There is a crow in my local park here, in Glasgow, Scotland, with a dramatic case of leucism. He (or she) operates entirely on their own. He’s easy to spot and rules over a small patch of territory that he never seems to leave. An interesting character!
We have a crow pair of parents raising four young in our adjacent wetlands this summer and they are astonishing to watch. <3
This is just fantastic.
There is a crow in my local park here, in Glasgow, Scotland, with a dramatic case of leucism. He (or she) operates entirely on their own. He’s easy to spot and rules over a small patch of territory that he never seems to leave. An interesting character!
I’ll look forward very much to the next chapter.